How do electrolytes affect conductivity and why does current increase with increase in temperature without changing voltage?
Dear Rk Naresh ,
each electrochemical cell (galvanic or electrolysis) consisted from electrodes with electronic conductivity and electrolyte with ionic conductivity, so this is closed circuit. the electrons are transported in outer part of this circuit, ions in electrolyte migrated from one electrode to other in solution ensure the current in inner part of this circuit. Voltage of any electrochemical cells U = Uocv +(-) Ulosses +(-) IR, where (+) for electrolysis cells, (-) for galvanic cells, I - passed current, R is inner resistance. The mostly the inner resistance is determined by electrolyte resistance. Electrolyte resistance depends on number of charges (ions) and forces of their interaction, so, the nature and electrolyte concentration, nature and viscosity of solvent are the factors strongly affected the ionic cunductivity.
The kinetics of Faraday (redox) reaction on the electrodes has an activation nature, viz. rate constant depends on temperature and overpotential similarly as Arrhenius equation (see Battler-Volmer equation), moreover, the potential of any electrode reaction formally is change of Gibbs energy of this reaction: E = - dG/nF, where n - number of electrons participating in reaction, F - Faraday constant, dG - changes of reaction Gibbs energy. So, the electrode potential also depens on temperature like Gibbs energy. Hope, my answer will be useful for your work.
Electrolytes release ions that increase solution conductivity. Conductivity increases with ion concentration and mobility. Temperature enhances ion mobility and conductivity of solution. Higher temperature reduces electrolyte resistance, allowing more charge carriers to flow and increasing current while maintaining voltage (Ohm's Law (V = IR)).
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